Core temperature (Tc) and the temperature of sensate skin (Tss) can be controlled independently in paraplegic man, an ideal experimental model for study of skin blood flow (SkBF) and sweat rate (SR) control mechanisms. We propose experiments which will critically test current concepts of how these input variables interact. Through analysis of the relationship between responses and level of lesion we should accomplish better understanding of how the input signals are processed at the level of central integration and may be able to determine extracerebral detection of Tc, e.g., spinal cord temperature (Tsc0, has a role in control of SR and SkBF. We expect to uncover new information on the dynamic aspects of control, i.e., whether rates of change and leads or lags substantially alter responses. On the effector side, we will examine the role of the renin-angiotensin system as a possible vasoconstrictor influence which offsets the effects of high SKBF in heated insenate skin; measurements of cardiac output will define the magnitude of the local and reflex responses in the cutaneous vascular bed below the lesion. These studies and the results of planned long-term temperature monitoring should have practical implications for understanding the character of the stresses encountered by paraplegics in hot environments and during exercise.